Size-Dependent Strength and Plasticity in Metallic Nanocrystalline-Amorphous Composites

金属纳米晶非晶复合材料中尺寸相关的强度和塑性

• 批准号: 430800-2013
• 负责人: Deng, Chuang
• 金额: $ 1.82万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=638175
• 关键词: Size; Dependent; Strength; Plasticity; Metallic

Materials that are strong and ductile are always favored and highly demanded by industry. However strength and ductility are usually anti-correlated in materials and are difficult to achieve simultaneously. While monolithic nanocrystalline metals and amorphous metallic glasses both exhibit higher strength as compared to conventional metals and alloys, their brittle natures severely limit their application as engineering materials. Some prior studies suggest that introducing a small portion of amorphous phase in nanocrystalline materials or vice versa can significantly improve the ductility of these materials without sacrificing the strength. For instance, exceptional tensile ductility up to ~13.8% elongation has been reported in crystalline Cu/CuZr glass nanolaminates as compared to < 2% in conventional nanocrystalline Cu. It has also been observed that introduction of ~7% volume fraction of nanocrystals can increase the compressive ductility of amorphous CuZr bulk metallic glass to > 5% from nearly zero. Although such investigations were based on trial-and-error and a deep understanding of the deformation mechanisms is still lacking, it opens the door to design materials and novel structures with desired strength and ductility at the same time. The applicant proposes to use mainly atomistic simulation and subsequent in-situ deformation experiments to study the strength and plasticity and their dependence on microstructures of crystalline/amorphous composites. The proposed study will significantly advance current understanding of the microplasticity in amorphous metallic glass and crystalline/amorphous composites in confined volumes. Ultimately, the research will contribute to the design of novel structures and materials with optimized combination of strength and ductility that can be used for various industrial applications, for example in microelectromechanical systems and nanoelectro-mechanical systems.

坚固且具有延展性的材料始终受到工业界的青睐和强烈需求。然而，材料中的强度和延展性通常是反相关的，并且很难同时实现。虽然单片纳米晶金属和非晶金属玻璃与传统金属和合金相比都表现出更高的强度，但它们的脆性性质严重限制了它们作为工程材料的应用。一些先前的研究表明，在纳米晶材料中引入一小部分非晶相或反之亦然可以显着提高这些材料的延展性而不牺牲强度。例如，据报道，结晶 Cu/CuZr 玻璃纳米层压材料具有高达约 13.8% 伸长率的优异拉伸延展性，而传统纳米晶 Cu 的拉伸延展性低于 2%。还观察到，引入约 7% 体积分数的纳米晶体可以将非晶 CuZr 大块金属玻璃的压缩延展性从接近零提高到 > 5%。尽管此类研究基于反复试验，并且仍然缺乏对变形机制的深入理解，但它为设计同时具有所需强度和延展性的材料和新颖结构打开了大门。申请人提出主要使用原子模拟和随后的原位变形实验来研究晶体/非晶复合材料的强度和塑性及其对微观结构的依赖性。拟议的研究将显着推进目前对有限体积内非晶金属玻璃和结晶/非晶复合材料微塑性的理解。最终，该研究将有助于设计具有强度和延展性优化组合的新型结构和材料，可用于各种工业应用，例如微机电系统和纳米机电系统。